Why commercial kitchen ductwork needs specialist cleaning
Commercial kitchen ductwork is the highest fire-risk ventilation in any UK building. Cooking emissions condense onto duct walls and harden into combustible grease — sometimes millimetres thick after only a few months of heavy service. Unlike comfort HVAC ductwork, kitchen extract ducts often run through ceiling voids, riser shafts and roof spaces, which means an extract-system fire can spread far beyond the kitchen before it is even detected.
TR19® Grease (BESA) is the recognised UK standard for cleaning, inspecting and verifying kitchen extract ductwork. It defines how often ductwork must be cleaned, what 'clean' means in terms of measured deposit thickness, how access must be provided, and what evidence must be produced afterwards. We deliver to that standard end-to-end.
What's included in a ductwork clean
- Pre-clean survey including duct geometry mapping and baseline deposit-thickness readings
- Isolation of cooking equipment and electrical/gas safe-system-of-work confirmation
- Mechanical agitation and rotary brushing of horizontal and vertical runs
- Hand cleaning around bends, dampers, attenuators and transitions
- Negative-pressure containment to prevent grease contamination of the kitchen
- Cleaning of fan housing, impeller and discharge cowl
- Installation of TR19-compliant access doors where required
- Post-clean deposit-thickness verification and full photographic record
- Signed TR19® certificate and recommended next-clean date
Access provision and BS EN 12097
TR19® requires that every section of ductwork can be inspected and cleaned. In practice we routinely find systems with no access doors, single doors at the canopy only, or access positions blocked by services. None of those configurations are compliant — and none can be properly cleaned.
Where we identify access shortfalls during the pre-clean survey we quote separately for installing fire-rated access doors at the spacing required by BS EN 12097. Once installed, the ductwork can be cleaned to standard, verified, and remain accessible for subsequent cleans and fire-risk inspections.
Verification and reporting
A clean is only compliant if it can be proven. We take deposit-thickness readings at agreed sample points along the duct run both before and after cleaning, using calibrated wet-film comb gauges. Those readings are recorded against duct schematics in your post-clean report.
Each report ships as a single PDF: site details, system description, methodology, before/after photographs at every access point, deposit measurements, the post-clean TR19® certificate and the recommended cleaning frequency. It is the evidence pack your insurer, FM team and fire-risk assessor will all ask for.
Frequently asked questions
Do you clean concealed ductwork in ceiling voids?+
Yes. We routinely clean ducts in suspended ceilings, riser shafts and roof voids. Where existing access is inadequate we install BS EN 12097 compliant access doors as part of the works.
How is cleaning verified?+
By measuring residual deposit thickness with calibrated wet-film gauges at agreed sample points and photographing every access opening before and after cleaning.